Illuminated control devices



June 7, 1966 M- M. GRAHAM ILLUMINATED CONTROL DEVICES Filed May 7, 1962 FIG.5

INVENTOR MARVIN M. GRAHAM BY FULWIDER, MATTINGLY & HUNTLEY ATTORNEYS United States Patent 3,254,534 ILLUMINATED CONTROL DEVICES Marvin M. Graham, San Pedro, Calif., assignor to Robertshaw Control Company, Richmond, Va., a corporation of Delaware Filed May 7, 1962, Ser. No. 192,828

4 Claims. (Cl. 73363.7)

The present invention relates generally to illuminated control devices, but more particularly to control devices having illuminated indicating means incorporated therein.

In the past, control devices have been provided with lighting means employing either carbon arc lamps or incandescent lamps. Such lighting devices have not proved entirely satisfactory for certain types of control devices since carbon arc lamps and incandescent lamps are essentially point sources of light of relatively high intrinsic brightness. Carbon arc lamps generate light as a result of a short path electric discharge through air, whereas incandescent lamps produce light as a result of the relatively high resistance to electric current flow exhibited by tungsten filaments. Such point sources of light not only produce an over supply of light at the lamp itself and an under supply of light at points remote therefrom, but also generate considerable heat. This characteristic seriously limits the application of certain control devices, since such extraneous source of heat can destroy theaccuracy of very sensitive temperature responsive devices.

Certain types of control devices, as for instance thermostatic devices and the like, are often located in areas which are, at certain times, poorly lighted. Since such devices usually require periodic adjustment, it is desirable that they be provided with lighting means. Also, since such devicesusually include a suitably calibrated dial and an indicator for cooperation therewith, it has been found most desirable to have light of constant intensity across the entire di-al, rather than to have one or more point sources of light as above described.

It is an object of the present invention to provide a self-illuminating control device.

It is an object of the present invention to provide an adjustable control device, the adjustment means of which is provided with light of substantially constant intensity.

Another object of this invention is to provide an adjustable control device having an adjustment dial the entire surface of which is aiforded light of substantially constant intensity.

Another object of the present invention is to teach the construction of an adjustable thermostatic control device having its own light source whereby suitable adjustments can be made to the device irrespective of variations in external ambient lighting conditions.

A further object of the present invention is to provide a control device as characterized above wherein an indicia-carrying dial also functions as the source of light for providing light of proper intensity thereacross.

A still further object of the present invention is to provide a control device as characterized above wherein the indicia-carrying dial member is formed of electroluminescent material.

It is also an object of the present invention to provide a control device as characterized above which is simple and inexpensive to manufacture and which is rugged and dependable in operation.

The novel features which I consider characteristic of my invention are set forth with particularity in the appended claims. The device itself, however, both as to its organization and mode of operation, together with additional objects and advantages thereof, will best be understood from the following description of specific em 3,254,534 Patented June 7, 1966 with the accompany- FIGURE 5 is a diagrammatic showing of the electrical circuitry of the present invention.

Like reference characters indicate corresponding parts throughout the several views of the drawings.

Referring to FIGURE 1 of the drawings, there is shown therein a preferred form of the present invention, such as control device 10 suitably mounted on a wall or panel 12. Control device 10 is a thermostatic control device which not only includes means for adjusting a response condition, as will hereinafter be explained in detail, but also carries suitable means for indicating variations in the condition being controlled. That is, device 10 of FIGURE 1 includes a temperature adjustment portion 10a and a temperature indicating or thermometer portion 10b.

The particular showing of a thermostatic device and the following description thereof are not to be interpreted as a limitation of the scope of the present invention. Rather, it is contemplated that the present invention can be applied, to advantage, to substantially any type or style of control device having an indicating dial or other type of indicia-carrying member which must be periodically viewed or adjusted. Y

Thermostatic device 10 comprises a base member 14 mounted, by suitable mounting bolts or screws, to the wall or panel 12, and a cup-shaped cover member 16 which cooperates with the base member to provide an enclosure. Within such enclosure and mounted on base member 14, as shown most clearly in FIGURE 4, is an encapsulated circuit controlling device 18 and a magnetic actuator 20 therefor. It has been found preferable to employ an hermetically sealed encapsulated circuit controlling device to prevent faulty or erratic operation due to accumulation of foreign material on the contacts of the circuit controlling device as frequently occurs when such contacts are exposed to atmospheric conditions.

Device 18 comprises a tubular envelope 22 having closed opposite end portions andwhich may be formed of substantially any non-magnetic material such as glass, plastic material or the like. Within hermetically sealed envelope 22 are two or more relatively movable electrical contacts,

' shown diagrammatically at 24 and 26 in FIGURE 5. One

such contact is mounted in a stationary position within envelope 22 while the other is pivotally mounted with respect thereto for movement between open and closed circuit conditions. Additionally, there is provided within envelope 22 a magnetic member (not shown) attached to or operatively associated with the movable contact for actuating the latter as will hereinafter be explained. Suitable lead wires as shown at 28 and 30 extend from enclosure 20 and are connected in circuit with the electrical contacts 24 and 26.

The actuating means-20 for switch 18 comprises a spirally wound bimetallic element 32 having a stationary inner end 32a and an extended, substantially straight outer end 32b. The outer end of bimetallic member 32 carries a mounting bracket 34 on which is mounted a permanent magnet 36 disposed adjacent circuit'controlling member 18 as shown most clearly in FIGURE 4.

A limit stop 38 is provided on base member 14 to limit the travel of magnetic member 36 away from circuit controlling device 18.

Magnetic member 36 is disposed adjacent device 18 such as to magnetically influence the movable electrical contact therewithin. As permanent magnet 36 approaches circuit controlling device 18 a point is reached where the magnetic lines of force from magnet 36 are sufiicient to influence the aforementioned magnetic member (not shown) associated with the movable electrical contact within enclosure 20 to move it into engagement with the aforementioned stationary contact. In this manner, the circuit to be controlled by device 18 is completed. As the permanent magnet 36 is moved away from the circuit controlling device 18 under the influence of bimetallic actuator 20 as will hereinafter be explained, a point is reached where the magnetic lines of force of member 36 are no longer sufiicient to retain the movable contact in its said closed circuit position against the biasing force of suitable biasing means (not shown) which is provided within enclosure 22 for that purpose.

Bimetallic element 32, of course, is formed of a pair of elements having dissimilar coefiicients of thermal expansion. As such, as the spirally Wound elements absorb and lose heat due to variations in ambient temperature to which they are exposed, they expand or contract by different amounts, the result being that the entire element 32 is deformed so as to be slightly wound or unwound from its previous condition. Since end 32a of bimetal 32 is stationary, such deformation effects movement of end 32b, and hence magnet 36, with respect to device 18.

The stationary end 32a of bimetal 32 is firmly secured to a pivot pin 40 which is pivotally carried by a mounting lever 45. An adjustment lever 44 is firmly attached to pin 40 such that movement of lever 44 effects rotation of pivot pin 40 with respect to mounting lever 45. The outer end 44a of member 44 is provided with a through opening for receiving one end 46a of a tension spring 46. The other end 46b of spring 46 is suitably attached to base member 14 as shown at 48.

Adjustment means in the form of a cam member 50 pivotally mounted on base 114 by means of a pivot pin 52 is provided for effecting movement of lever 44 against the force of tension spring 46. Such cooperation between cam member 50 and lever 44 is effected by means of an arm (not shown) which extends laterally from lever 44 for engagement with cam surface 50a of cam member 50. The cam surface is so designed that as pin 52 is rotated in a counterclockwise direction as viewed in FIGURE 4, the pivotal lever 44 is moved correspondingly in a counterclock-wise direction against the force of spring 46. Such action, of course, causes pin 40 to be pivoted in a counterclockwise direction so as to cause the bimetallic member 32 to move magnetic member 36 away from the circuit controlling device 18.

The cam surface 50a of member 50 is formed with an indicator point 50b in close proximity to suitable indicia as shown at 54 on base member '14. Such indicia, as will hereinafter become more apparent, may be calibrated to indicate temperature if desired, and in any event, constitutes a reference for the adjustment of cam member 50.

The upper end portion of pivot pin 52 is provided with a fiat 52a.

Also mounted on base 14 is a manually operable circuit controlling device or switch 56 having an actuating lever 56a. Switch 56 is connected in circuit with the electrical contacts 24 and 26 of device 18 as will hereinafter be described with reference to FIGURE of the drawings.

A transformer 58 having input leads 60 and 62 and output leads 64 and 66 is also mounted on 'base 14. Input leads 60 and 62 extend from the control device for connection to a suitable source of power as 'Will hereinafter be described.

The output leads 64 and 66 of transformer 58 are connected to electrical terminals which are recessed within tubular housings 68 and 70 formed on base 14. It is contemplated that base member 14 may be molded of plastic materials, and hence the tubular housings 68 and 70 may be formed integral therewith. However, in the alternative such housings could be formed separately and attached to base 14 if desired.

As shown most clearly in FIGURE 2 of the drawings, each of the tubular housings 68 and 70 is formed with a through opening having a reduced portion as a result of an annular shoulder or flange as shown at 68a. A terminal member 74 is provided in each of the housings 68 and 70, the terminal member 74 shown in FIGURE 2 being provided with an enlarged end portion 74a. A compression spring 72 is interposed between the end portion 74a of terminal member 74 and the annular shoulder 68a.

Terminal member 74 has an elongated shank 74b which extends through the reduced portion of the opening formed in housing 68. The lower end of shank 74b is staked or is provided with suitable fastening means to provide a limit stop for the upward movement of terminal 74 by compression spring 72. The output leads 64 and 66 from transformer 58 are individually attached to the terminals through suitable transverse openings in the side wall of the tubular housings 68 and 70.

The cup-shaped cover 16 may also be formed of plastic, and is generally of such size and shape as to resiliently engage base 14. If desired, suitable interlocking indentations and protuberances may be provided on the members 14 and 16 to insure firm engagement of the cover on the base member.

Cover 16 is provided with an indicia-carrying plate which is firmly fastened to the outer face of the cover and is provided with a generally circular outer periphery and is formed with a circular centrally located opening. Member 80 of FIGURE 1 is provided with suitable temperature indicia 82 arranged arcuately along its upper edge and corresponding temperature indicia 84 similarly arranged along its bottom edge. Indicia 82 and 84 may be applied in any appropriate manner, such as by being painted, etched, carved, or the like in indicia plate 80.

As will hereinafter be described in further detail, the indicia plate 80 also constitutes the light source for the entire control device 10. Such plate 89 is formed of electroluminescent material which may comprise phosphor suspended in a dielectric medium. Such electroluminescent materials are of laminated construction and are readily available in todays commercial market places.

Pivotally mounted on the cover 16 of device 10 is a transparent adjusting member or knob 86 which carries an indicating mark or point 88 at one location adjacent its outer periphery. The entire peripheral edge of adjustment member 86 may be knurled to provide finger gripping means for easy rotation of member 86. The central portion 86b of adjusting member 86 may be non-transparent and may carry suitable advertising if desired.

As shown most clearly in FIGURE 3 of the drawings, the adjusting member 86 is pivotally mounted within a centrally located opening 16a in cover 16. For this purpose, member 86 is provided with a shaft 860 which is formed with an opening having a flat 86d corresponding to the flat 52a on the upper end portion of pivot pin 52.

Positioned behind the non-transparent central portion 86b of member 86 is a temperature responsive device as for instance a bimetallic -element 89 which carries an indicator 90 which is movable with respect to the temperature scale having indicia 84 for indicating the prevailing ambient temperature.

Cover 16 is further formed with an arcuate opening 16b adjacent opening 16a. A pair of lead wires 92 and 94 extend through opening 16b and are connected to opposite sides of the aforedescribed electroluminescent indiciacarrying member 80. Lead wire 92 is connected to a terminal post 96 which is rigidly attached to the underside of cover 16 and depends therefrom as shown in FIG- URE 2. In like manner, lead wire 94 is connected to a shoulder or flange as shown at 96a and 98a respectively.

The lead wires 92 and 94 are connected to such terminal members at such flanges.

The terminal members 96 and 98 are insulatedly mounted on the cover 16 so that the electricalcircuit therebetween is through the electroluminescent indiciacarrying member 80. In this regard, the lead wires.92 and 94 may be connected to opposite surfaces of the plate 80 by any appropriate means as for instance clips or small bolts (neither of which is shown in the drawings).

It isthus seen that by positioning cover 16 on base member 14 the adjustment member 86 is connected to the cam member 50 through the hollow shaft 86a of member 86 and the pivot pin 52 which carries cam member 50. Engagement of the flats 86c and 52a insures that rotation of adjustment member 86 on cover 16 will vary the position of cam member 50.

Referring to FIGURE of the drawings, the thermostatic device is shown therein within the broken line 10.

The domestic heating apparatus to 'be controlled by device is connected to the usual household source of electrical energy of 110 volts. A transformer 100 has its primary winding 102 connected to the 110 volt source. The secondary winding 104 of transformer 100 affords approximately 24 volts for energizing a solenoid operated flow control valve 106 which is connected in the fuel supply conduit of the main burner of the heating unit.

in engagement with a valve seat 1060 to flow permitting position in. spaced relation thereto. When this occurs, combustible fuel is permitted to fiow from the inlet 106d to the outlet 1062 of the valve 106 to afford fuel flow to the main burner of the heating unit.

One side of secondary winding 104 is connected to one side of electromagnetic winding 106a of valve 106. The other side of winding 106a is connected to lead wire of thermostatic device 10.

Lead wire 28 from circuit controlling device 18 is connected to one terminal of the manually operable switch 56. The movable contactor 56a of switch 56 is connected to the other side of secondary winding 104 of transformer 100 through a lead wire 108.

Switch 56 is shown diagrammatically in FIGURE 5 of the drawings as having three positions. When in a first position in engagement with stationary contact 56b, movable contactor 56a completes the heating circuit for energization of valve 106 in response to operation of circuit controlling device 18. The remaining stationary contacts 560 and 56d can be used respectively to afford an off position for the entire control apparatus and a cooling or air-circulating position if desired. That is, whereas stationary contact 560 might represent an off position, when contactor 56a is in engagement with contact 56d an air circulating fan which'is part of the heating unit can be energized or an entire air refrigerating system can be energized. Neither of such devicesor apparatuses is shown in the drawing.

The input leads 60 and 62 of transformer 58 are connected across the secondary winding 104 of transformer 100. Transformer 58 is so constructed that when 24 volts is impressed across its primary winding 58a a potential of approximately 70 volts is developed across the secondary winding 58b thereof. This is necessary since approximately 70 volts is necessary for properly energizing the electroluminescent indicia plate 80. As shown in FIGURE 5 of the drawings, the plate is connected in series circuit arrangement with the secondary winding 5850f transformer 58 through the aforedescribed terminal members 96 and 98 on cover 16 and tubular terminal members'63 and 70 on base member 14. In this manner an electrical potential of 70 volts is impressed across the opposite faces of the electroluminescent member 80. This causes the entire member 80 to constitute What is commonly termed an area source of light. Thus, the entire indicia-carrying member 80 glows so as to afford constant light intensity over the entire Upon removal of cover 16 from base 14, the terminal .posts 96 and 98 are separated from their respective terminal members within the housings 68 and 70. Thus the 70 volt potential aiforded by transformer 58 is not exposed for possible contact by service personnel.

With cover 16 properly positioned on base member 14 not only is adjustment member 86 properly connected to cam'member 50 through shaft 860 and pin 52, but suitable electrical potential is aiforded across plate 80. Thereafter variations in ambient temperature effect deformation of the bimetal 32 so as to effect operation of switch 18. Operation of the latter, of course, controls the energization and de-energization of winding 106a of flow control device 106.

The response temperature of device 10 can be readily changed by suitable manipulation of adjustment member 86. Rotating member 86 so as to align indicating pointer 88 with the proper graduation in the temperature scale having indicia 82 causes cam member 50 and spring 46 to alter the position of stationary end portion 32a of bimetal 32. Such action, of course, alters the relationship between magnet 36 and switch 18. Thus, the response temperature of device 10 is altered as desired.

It is thus seen that the present invention provides a control device which is easier. to adjust and which is easier to view under adverse ambient lighting conditions.

Although I have shown and described certain specific embodiments of my invention I am fully aware that many modifications thereof are possible. My invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and by the spirit of the appended claims.

I claim: 1. A self-illuminated room thermostat, comprising: an enclosure having a basemember and a cover on said base member having a portion formed of electroluminescent material, said portion of said cover be ing provided with ambient temperature indicia and response temperature indicia; adjustable temperature responsive means in said enclosure; 7

an adjustable knob supported on said enclosure over said cover and operatively connected to said adjustable temperature responsive means, said adjustment knob being cooperable with said response temperature indicia on said cover;

ambient temperature means on said cover cooperable with said ambient temperature indicia to provide an indication of room temperature;

and means on said enclosure for electrically energizing 7 said electroluminescent materialto cause said material to afford light and thereby facilitate adjustment of said adjustment knob with respect to said response temperature indicia.

2. A self-illuminated room thermostat as set forth in claim 1 wherein, said means for electrically energizing said electroluminescent material includes complemental, normally electrically connected circuit components carried by said cover and said base member, respectively, and electrically disconnectable when dernounting said cover from said base member to thereby de-energize said electroluminescent material.

3. A self-illuminated room thermostat as set forth in claim 1 wherein, said means for electrically energizing said electroluminescent material includes a transformer. 4. A self-illuminated room thermostat as set forth in claim 2 wherein, said means for electrically energizing said electroluminescent material includes a transformer.

References Cited by the Examiner UNITED STATES PATENTS ISAAC LISANN, Primary Examiner.

NEIL C. READ, Examiner.

15 R. M. ANGUS, J. H. BARKSDALE,

Assistant Examiners. 

1. A SELF-ILLUMINATED ROOM THERMOSTAT, COMPRISING: AN ENCLOSURE HAVING A BASE MEMBER AND A COVER ON SAID BASE MEMBER HAVING A PORTION FORMED OF ELECTROLUMINESCENT MATERIAL, SAID PORTION OF SAID COVER BEING PROVIDED WITH AMBIENT TEMPERATURE INDICIA AND RESPONSE TEMPERATURE INDICIA; ADJUSTABLE TEMPERATURE RESPONSIVE MEANS IN SAID ENCLOSURE; AN ADJUSTABLE KNOB SUPPORTED ON SAID ELEMENT OVER SAID COVER AND OPERATIVELY CONNECTED TO SAID ADJUSTABLE TEMPERATURE RESPONSIVE MEANS, SAID ADJUSTMENT KNOB BEING COOPERABLE WITH SAID RESPONSE TEMPERATURE INDICIA ON SAID COVER; AMBIENT TEMPERATURE MEANS ON SAID COVER COOPERABLE WITH SAID AMBIENT TEMPERATURE INDICIA TO PROVIDE AN INDICATION OF ROOM TEMPERATURE; AND MEANS ON SAID ENCLOSURE FOR ELECTRICALLY ENERGIZING SAID ELECTROLUMINESCENT MATERIAL TO CAUSE SAID MATERIAL TO AFFORD LIGHT AND THEREBY FACILITATE ADJUSTMENT OF SAID ADJUSTMENT KNOB WITH RESPECT TO SAID RESPONSE TEMPERATURE INDICIA. 